Optical fibers are often used to transmit optical signals between optical elements. Sometimes it is desirable to add an optical signal received from an optical device via a branch optical fiber to a main optical fiber, or to extract a sample of the optical signal passing through the main optical fiber and to transmit the sample to another optical device via the branch optical fiber. For example, the main optical fiber may distribute an optical network signal to subscribers located along a city street. When new customers subscribe to the network service, additional signal connections may need to be made to the main optical fiber.
Establishing such additional signal connections has conventionally required that the main optical fiber be severed. This process may be time-consuming, results in an interruption of the signal transmission through the main optical fiber and reduces the reliability of the optical main fiber.
Thus, what is needed is an optical fiber tap that enables a branch optical fiber to be coupled to a main optical fiber at any point along the main optical fiber to enable an additional signal connection to be made without severing the main optical fiber.
The invention provides an optical fiber tap for establishing optical communication between a branch optical fiber and a main optical fiber. The optical fiber tap is capable of random placement along the main optical fiber. The optical fiber tap includes a housing, a serpentine main channel and a branch channel. The main channel is defined in the housing and is shaped to accommodate part of the main optical fiber. The main channel includes a coupling curve portion shaped to define a main coupling curve in the main optical fiber. The branch channel is also defined in the housing and is shaped to accommodate part of the branch optical fiber. The branch channel communicates with the main channel at the coupling curve portion of the main channel. Optical signals couple laterally between the main optical fiber located in the main channel and the branch optical fiber located in the branch channel. Optical communication between the optical fibers is therefore established.
In one embodiment, the branch channel is serpentine and includes a coupling curve portion opposed to and juxtaposed with the coupling curve portion of the main channel. Optical signals couple laterally between the juxtaposed, opposed coupling curves formed by the main channel in the main optical fiber and by the branch channel in the branch optical fiber. Optical communication is therefore established between the optical fibers.
In another embodiment, the branch channel includes an end-stop located adjacent the coupling curve portion of the main channel. The end-stop locates one end of the branch optical fiber at the coupling curve portion of the main channel. Optical signals couple laterally between the coupling curve formed by the main channel in the main optical fiber and the end of the branch optical fiber. Optical communication is therefore established between the optical fibers.